Partial migration, where populations are composed of both migratory and resident individuals, is extremely widespread across the animal kingdom. Researchers studying fish movements have long recognized that many fishes are partial migrants, however, no detailed taxonomic review has ever been published. In addition, previous work and synthesis has been hampered by a varied lexicon associated with this phenomenon in fishes. In this review, definitions and important concepts in partial migration research are discussed, and a classification system of the different forms of partial migration in fishes introduced. Next, a detailed taxonomic overview of partial migration in this group is considered. Finally, methodological approaches that ichthyologists can use to study this fascinating phenomenon are reviewed. Partial migration is more widespread amongst fishes than previously thought, and given the array of techniques available to fish biologists to study migratory variation the future of the field looks promising.

Antitumor necrosis factor-α (TNF-α) is used for treatment of severe cases of inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). However, one-third of the patients do not respond to the treatment. Genetic markers may predict individual response to anti-TNF therapy. Using a candidate gene approach, 39 mainly functional single nucleotide polymorphisms (SNPs) in 26 genes regulating inflammation were assessed in 738 prior anti-TNF-naive Danish patients with IBD. The results were analyzed using logistic regression (crude and adjusted for age, gender and smoking status). Nineteen functional polymorphisms that alter the NFκB-mediated inflammatory response (TLR2 (rs3804099, rs11938228, rs1816702, rs4696480), TLR4 (rs5030728, rs1554973), TLR9 (rs187084, rs352139), LY96 (MD-2) (rs11465996), CD14 (rs2569190), MAP3K14 (NIK) (rs7222094)), TNF-α signaling (TNFA (TNF-α) (rs361525), TNFRSF1A (TNFR1) (rs4149570), TNFAIP3(A20) (rs6927172)) and other cytokines regulated by NFκB (IL1B (rs4848306), IL1RN (rs4251961), IL6 (rs10499563), IL17A (rs2275913), IFNG (rs2430561)) were associated with response to anti-TNF therapy among patients with CD, UC or both CD and UC (P ⩽ 0.05). In conclusion, the results suggest that polymorphisms in genes involved in activating NFκB through the Toll-like receptor (TLR) pathways, genes regulating TNF-α signaling and cytokines regulated by NFκB are important predictors for the response to anti-TNF therapy among patients with IBD. Genetically strong TNF-mediated inflammatory response was associated with beneficial response. In addition, the cytokines IL-1β, IL-6 and IFN-γ may be potential targets for treating patients with IBD who do not respond to anti-TNF therapy. These findings should be examined in independent cohorts before these results are applied in a clinical setting.

BackgroundThe inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), result from the combined effects of susceptibility genes and environmental factors. Polymorphisms in genes regulating inflammation may explain part of the genetic heritage.MethodsUsing a candidate gene approach, 39 mainly functional single nucleotide polymorphisms (SNPs) in 26 genes regulating inflammation were assessed in a clinical homogeneous group of severely diseased patients consisting of 624 patients with CD, 411 patients with UC and 795 controls. The results were analysed using logistic regression.ResultsSixteen polymorphisms in 13 genes involved in regulation of inflammation were associated with risk of CD and/or UC (p≤0.05). The polymorphisms TLR2 (rs1816702), NFKB1 (rs28362491), TNFRSF1A (rs4149570), IL6R (rs4537545), IL23R (rs11209026) and PTPN22 (rs2476601) were associated with risk of CD and the polymorphisms TLR2 (rs1816702), TLR4 (rs1554973 and rs12377632), TLR9 (rs352139), LY96 (rs11465996), NFKBIA (rs696), TNFA (rs1800629), TNFRSF1A (rs4149570), IL10 (rs3024505), IL23R (rs11209026), PTPN22 (rs2476601) and PPARG (rs1801282) were associated with risk of UC. When including all patients (IBD) the polymorphisms TLR2 (rs4696480 and rs1816702), TLR4 (rs1554973 and rs12377632), TLR9 (rs187084), TNFRSF1A (rs4149570), IL6R (rs4537545), IL10 (rs3024505), IL23R (rs11209026) and PTPN22 (rs2476601) were associated with risk. After Bonferroni correction for multiple testing, both the homozygous and the heterozygous variant genotypes of IL23R G>A(rs11209026) (ORCD,adj: 0.38, 95% CI: 0.21–0.67, p = 0.03; ORIBD,adj 0.43, 95% CI: 0.28–0.67, p = 0.007) and PTPN22 1858 G>A(rs2476601) (ORCD,unadj 0.54, 95% CI: 0.41–0.72, p = 7*10−4; ORIBD,unadj: 0.61, 95% CI: 0.48–0.77, p = 0.001) were associated with reduced risk of CD.ConclusionThe biological effects of the studied polymorphisms suggest that genetically determined high inflammatory response was associated with increased risk of CD. The many SNPs found in TLRs suggest that the host microbial composition or environmental factors in the gut are involved in risk of IBD in genetically susceptible individuals.

Summary Background Anti‐tumor necrosis factor‐α (TNF‐α) is used for the treatment of severe cases of IBD, including Crohn's disease (CD) and ulcerative colitis (UC). However, one‐third of the patients do not respond to the treatment. We have previously investigated whether single nucleotide polymorphisms (SNPs) in genes involved in inflammation were associated with response to anti‐TNF therapy among patients with CD or UC. Aim A new cohort of patients was established for replication of the previous findings and to identify new SNPs associated with anti‐TNF response. Methods Fifty‐three SNPs assessed previously in cohort 1 (482 CD and 256 UC patients) were genotyped in cohort 2 (587 CD and 458 UC patients). The results were analysed using logistic regression (adjusted for age and gender). Results Ten SNPs were associated with anti‐TNF response either among patients with CD (TNFRSF1A(rs4149570) (OR: 1.92, 95% CI: 1.02‐3.60, P = 0.04), IL18(rs187238) (OR: 1.35, 95% CI: 1.00‐1.82, P = 0.05), and JAK2(rs12343867) (OR: 1.35, 95% CI: 1.02‐1.78, P = 0.03)), UC (TLR2(rs11938228) (OR: 0.55, 95% CI: 0.33‐0.92, P = 0.02), TLR4(rs5030728) (OR: 2.23, 95% CI: 1.24‐4.01, P = 0.01) and (rs1554973) (OR: 0.49, 95% CI: 0.27‐0.90, P = 0.02), NFKBIA(rs696) (OR: 1.45, 95% CI: 1.06‐2.00, P = 0.02), and NLRP3(rs4612666) (OR: 0.63, 95% CI: 0.44‐0.91, P = 0.01)) or in the combined cohort of patient with CD and UC (IBD) (TLR4(rs5030728) (OR: 1.46, 95% CI: 1.01‐2.11, P = 0.04) and (rs1554973)(OR: 0.80, 95% CI: 0.65‐0.98, P = 0.03), NFKBIA(rs696) (OR: 1.25, 95% CI: 1.01‐1.54, P = 0.04), NLRP3(rs4612666) (OR: 0.73, 95% CI: 0.57‐0.95, P = 0.02), IL1RN(rs4251961) (OR: 0.81, 95% CI: 0.66‐1.00, P = 0.05), IL18(rs1946518) (OR: 1.24, 95% CI: 1.01‐1.53, P = 0.04), and JAK2(rs12343867) (OR: 1.24, 95% CI: 1.01‐1.53, P = 0.04)). Conclusions The results support that polymorphisms in genes involved in the regulation of the NFκB pathway (TLR2, TLR4, and NFKBIA), the TNF‐α signalling pathway (TNFRSF1A), and other cytokine pathways (NLRP3, IL1RN, IL18, and JAK2) were associated with response to anti‐TNF therapy. Our multi‐SNP model predicted response rate of more than 82% (in 9% of the CD patients) and 75% (in 15% of the UC patients), compared to 71% and 64% in all CD and UC patients, respectively. More studies are warranted to predict response for use in the clinic.